Boris Johnson will officially open the line at 9.45 tomorrow morning in Dalston Junction station.

Opposition leaders on the London Assembly have been invited, but are unlikely to attend due to concerns that Boris will turn it into a campaign event.

Liberal Democrat Chair of the london Assembly Transport Committee Caroline Pidgeon said today:

"Right in the middle of a General Election campaign, the Mayor is desperate to claim credit for something he didn't initiate. The East London Line opening will be welcomed by many Londoners, but must not be used as a political football.

"The fact that two 'official openings' have already been postponed on technical grounds clearly demonstrates that political convenience has been the key factor driving the date of the official opening."

Transport for London have denied this and insist that the Mayor's attendance will help publicise the line and increase their revenue.

A senior source in the organisation told me earlier this month:

"We want the revenue and the experience of people using it and we want the exposure the Mayor will get us by opening it...

"Ken Livingstone would have not given it a second thought to open a £1billion new railway for London and his reason for doing so would have been the same as ours, which is that it is a great thing for London."

A limited "preview service" will run on the Dalston - New Cross section for the next month, with a full service commencing towards the end of May.

“The re-opened, improved and extended East London Line, built with Labour investment, is a big advance for people in East and South London and when it is linked up with the east-west Crossrail we will see a further quantum leap forward for public transport in our city. Without the decision in 2003 to go ahead and deliver this line in time for the Olympics, with £1bn investment from the Government, we would not have won our bid to host the Games.

"It is now clear that Conservatives will not commit to the construction of Crossrail, which is vital for business, jobs and economic growth in London. This in stark contrast to Labour's clear and unequivocal commitment to Crossrail which will add ten per cent to London's tube and rail capacity, create 14,000 jobs in the construction period alone and add an estimated £20billion to London's economy.

“The Conservatives’ repeated failure to give this clear commitment shows they cannot be trusted to secure the recovery and invest for London’s future.”